First of all.. You must buy a welder. I have a 110 Hobart Handler 140 which is a great machine. Learning to weld takes a few days., you will get better ad time goes by. For anyone who is creative and handy building things at home is fun and will save you thousands of dollars. You can build a custom crossember for $50. I have built two.. My first long arm crossmember was a modified OEM crossmember with long arm mounts.
You can take a stock crossmember and customize it to include long arm mounts. It's not hard work. Plan ahead, do sketches on paper, then start working.
You can buy brackets from Ballistic Fabrication which you weld to your crossmember. I shaved the bottom off my ctossmember and played the bottom side with 1/4 plate across. This plate needs to be welded very strong and then y
You can weld your bracketry to this heavy steel. Welding to the stock crossmember without any reinforcing isn't a good idea because the material is thin.
Once your long arm crossmember is finished, use grade 8 hardware to bolt it in place. Once your new mounts are in place.. You can then build your long arms. I recommend Y Link radius arms because they work well and you only need 2 rear mounting brackets.
Here is my first long arm crossmember, a modified OEM unit with Ballistic brackets and reinforcing. I ran this design in addition to a Rustys transfercase skid plate. I had no problems at all. This cost me approx $40 to make at home. The long arm length with this set up are a Y link design LCAs being 33" in length.
Right now I am building a new, ultra beefy new custom crossmember/skid/long arm mounts. This new unit bolts through the frame rails, instead of up Into the frame rails. This new crossmember is moved back about 8" from the oem crossmember location. This new unit is very strong, supports the tranny & case and protects the transfercase and most importantly gives me a high clearance mounting location for my new long arms. NOTHING in this design hangs below the bottom of the frame rails. The goal when building a crossmember is to keep everything tucked up high inside the frame rails. There are many belly pan designs out there, but they are $400. I built this with steel from my garage, some 1/4 plate, 2x2 tubing, some 1.25" tube and a simple hand grinder with cutting wheel, a drill, and a Hobart welder.
It's a fun project but this xmember holds your entire front end in place! Spbit must be strong! Think about what u want, what your long arm end joints will be (poly, heim or flex) joints and the bolt size.